Toilet bowl cleaners, such as those in the form of lavatory cleansing blocks and automatic toilet bowl cleanser dispensers, are well known.
Conventional lavatory cleansing blocks are placed directly into a toilet tank without the use of dispensing devices. In this way, the lavatory cleansing blocks are allowed to settle to the bottom of the toilet tank, typically assisted by the addition of a salt to "weight" down the lavatory cleansing blocks. The lavatory cleansing blocks then dissolve slowly over time thereby releasing to the toilet water the cleansing agents contained therein. Such known lavatory cleansing blocks are typically formulated with sufficient amounts of water-insoluble surfactants to increase the time the lavatory cleansing blocks may exist in the toilet tank without completely dissolving.
The water solubility of the known lavatory cleansing blocks is often controlled by employing a hydrophobic or water-insoluble material in combination with a water-soluble surfactant. For example, U.S. Pat. Nos. 4,722,802 (Hutchings et al.) and 4,269,723 (Barford et al.) refer to a composition and process for making lavatory blocks from the composition. The Barford patent also describes the inclusion of other water-insoluble release agents, such as clays and water-dispersible polymers, in the compositions. In addition, U.S. Pat. Nos. 4,043,931 (Jeffrey et al.) and 4,308,625 (Kitko) refer to compositions said to be useful for lavatory cleansing blocks, that employ two nonionic surfactants, one of which is relatively water-insoluble and the other of which is relatively water-soluble. U.S. Pat. No. 4,820,449 (Menke et al.) also refers to a lavatory cleansing block which comprises water-soluble surfactants, such as C.sub.12 -C.sub.14 alkyl sulfate sodium salts, and water-insoluble surfactants, such as mono- or di-alkanolamides. U.S. Pat. No. 4,722,801 (Bunczk et al.) refers to lavatory block compositions whose rate of dissolution is controlled through the use of polyethylene glycol distearate. Lavatory cleansing blocks so prepared impart surfactants to the flush water as cleansers and detergents at a rate that allows these blocks to have longer effective in-use life-spans than lavatory cleaning blocks prepared without the hydrophobic/water-insoluble material, which dissolve in the water of the toilet tank much more readily.
However, these types of lavatory cleansing blocks have certain drawbacks. For instance, in controlling the rate of water solubility, the hydrophobic or water-insoluble materials included in the lavatory cleansing block compositions (1) commonly add excess weight and bulk to the lavatory cleansing blocks; (2) compromise the effectiveness of the active ingredient(s) (e.g., cleansing and disinfectant agents and the like) in the lavatory cleansing blocks due at least in part to the deposition of water-insoluble materials on the surfaces of the toilet tank and toilet bowl which remain over long contact times; and (3) make the availability of active ingredient in the lavatory cleansing blocks sensitive to differences in turbulence and water temperature found in toilets throughout the United States.
In addition, use of these hydrophobic/water-insoluble materials in lavatory cleansing blocks fosters inconsistent delivery to the flush water of the active ingredients, with the quiescent period between flushes dictating the delivered concentration of those ingredients. That is, while such lavatory cleansing blocks tend to deliver a concentrated amount of active ingredient when the toilet is flushed after having been in the quiescent period between flushes for prolonged periods of time, they tend to deliver a more dilute amount of active ingredient after repeated or frequent flushes of the toilet.
Overcoming any or all of these problems would be met with keen consumer and commercial interest.
Dispensers have also been widely used to deliver predetermined amounts of liquid toilet cleansers to the toilet bowl. See e.g., U.S. Pat. Nos. 4,459,710 (Keyes et al.), 4,707,865 (Ludwig et al.), 4,707,866 (von Philipp et al.) and 4,764,992 (Delia). Certain of these dispenser have typically been characterized as "active" dispensers since valves or other mechanisms are used to initiate flow from the dispenser when the toilet tank is emptied to a given level. Others of these dispensers have been characterized as "passive" dispensers when no moving parts are used and the predetermined amount of liquid cleanser is dispensed solely by the actuation of the lowering of the water level in the toilet tank. See e.g., U.S. Pat. No. 4,745,638 (Richards), and the U.S. patents referred to therein.
Often, the passive dispensers deliver the liquid toilet cleansers by means of an air lock, a siphon or a combination thereof. The intent of these delivery means is to prevent uncontrolled diffusion between the liquid toilet cleanser and the water in the toilet tank. In addition, with these delivery means, all of the predetermined amount of liquid toilet cleanser typically evacuates from the dispenser into the toilet tank, leaving substantially no residual volume of liquid toilet cleanser remaining in the dispenser.
Such conventional dispensers are also typically sealed, either permanently or temporarily. Even when a temporary seal is used, many consumers generally remove the dispensers from the toilet tank to replenish the supply of liquid or solid toilet cleanser. Accordingly, a dispenser which is refillable but not sealed would result in greater commercial acceptance. Moreover, many consumers discard temporarily sealed dispensers rather than replenish their supply of liquid or solid toilet cleanser. In the latter case, an environmental concern is raised. In that vein, a refillable dispenser should reduce the amount of waste created by reducing the number and frequency of discarded dispensers. Therefore, there is a need for a lavatory cleansing system that delivers to the toilet bowl a lavatory cleanser composition with an enhanced degree of concentration consistency when the toilet is flushed frequently or repetitively. There is also a need for disposing within the dispenser a concentrated or viscous liquid lavatory cleanser composition which may be diluted, or a solid lavatory cleanser composition which may be solubilized to provide an effective amount of lavatory cleanser when the toilet is flushed with enhanced consistency from flush-to-flush. There is a need for a lavatory cleanser composition that contains fewer or none of the hydrophobic/water-insoluble materials found in conventional lavatory cleansing blocks so that the effectiveness of the cleanser is not compromised by water-insoluble deposits. In addition, there is a need for a lavatory cleansing system which counters the affect of sensitivity to differences of water turbulence in toilet tanks on the life-span of conventional lavatory cleaning blocks. And there is a need for an easily refillable dispenser for use in a lavatory cleansing system.
In meeting those needs, it would be desirable to provide a dispenser that may use in conjunction therewith a lavatory cleanser composition whose rate of solubility may be controlled by the dispenser and allows for effective delivery to the toilet tank over extended periods of time. It would also be desirable to provide such a dispenser that is easily refillable while mounted for use in a toilet tank.